ANTHRAQUINONES FROM NEONAUCLEA-CALYCINA AND THEIR INHIBITORY ACTIVITYAGAINST DNA TOPOISOMERASE-II

In a series of searches for DNA topoisomerase II inhibitors from natur ally occurring compounds, a wood extract of Neonauclea calycina MERR, (Rubiaceae) showed a moderate effect in vitro, Purification of the ext ract resulted in the isolation of seven known anthraquinones. The stru ctures were characterized as damnacanthal, biadin 1-methyl ether, nord amnacanthal, morindone, damnacanthol, lucidin 3-O-primeveroside and mo rindone 6-O-primeveroside by spectral analysis, respectively. Damnacan thal and morindone showed an intensive inhibitory effect against topoi somerase II (IC50: 20 mu g/ml and 21 mu g/ml).